Play every tab's preview straight into the master (#368)

Since #351 the tabs played their asset along its links in the Master
routing, as the game does. A song linked into a reverb bus was heard
through that bus while it was edited. A preview should sound like the
asset itself, so the tabs leave the Master routing out again.

- The Sound, Sound FX, Instrument, Pattern and Song tab play into the
  master. The sound FX of the asset still applies, and so does the
  master's own volume and FX.
- Inside a song its own routing of tracks and sends still counts.
- The game is unchanged: Play nodes go along the routing as before.

Tests:
- e2e 34 (melektaus-atx): ALL PASSED, 96 checks. The routing check
  now holds the mix of the two buses as before, and the Sound tab on
  the master with the bus silent.
- Counter-probe e2e: the Sound tab along the routing again, the
  routing check red.
- Gate (melektaus-atx): CHECK EXIT 0, 274 files, 4230 tests.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/editor/soundfx/SoundFxEditor.ts

@@ -7,7 +7,7 @@ import { volumeOf } from '../../core/properties/sounds';
 import { soundFxBuildFor, soundFxParams } from '../../core/soundfx/compile';
 import { Button, Dropdown, HStack, Label, Menu, NumberField, Stack, Theme } from '../../ui';
 import { soundLibrary } from '../../viewport/SoundLibrary';
-import { playedBus } from '../../core/music/mixer';
+import { MASTER_MIX } from '../../core/music/mixer';
 import { AssetTabEditor } from '../AssetTabEditor';
 import { GraphCanvas } from '../graph/GraphCanvas';
 import { SnapToggle } from '../graph/SnapToggle';
@@ -106,10 +106,9 @@ export class SoundFxEditor extends AssetTabEditor<SoundFxAsset, GraphCanvas> {
     if (!sound?.asset.file || !plan) return;
     const props = resolveAssetProps(this.state.project, sound.asset);
     const fx = { plan, params: { ...this.values } };
-    // Along the routing of the sound, as the game would play it there (#351).
-    const bus = playedBus(this.state.project, '', sound.asset.id);
+    // Straight into the master: a preview leaves the routing of the sound out (#368).
     const file = playedSoundOf(sound);
-    const voice = soundLibrary.play(file, volumeOf(props), false, PREVIEW_OWNER, fx, bus);
+    const voice = soundLibrary.play(file, volumeOf(props), false, PREVIEW_OWNER, fx, MASTER_MIX);
     if (voice) this.voices.push(voice);
     this.playedFor = asset.id;
   }